# 51. Let Q ($\sqrt\gamma$) be the BER of a BP...

51. Let Q ($\sqrt\gamma$) be the BER of a BPSK system over an AWGN channel with two-sided noise power spectral density N0/2. The parameter $\gamma$ is a function of bit energy and noise power spectral density.  A system with tow independent and identical AWGN channels with noise power spectral density N0/2 is shown in the figure. The BPSK demodulator receives the sum of outputs of both the channels.

If the BER of this system is $Q(b\sqrt\gamma)$ then the value of b is _____________.